1. Field of the Invention
The present invention relates generally to signal measurement systems and, more particularly, to enabling an operator to annotate trigger specifications and displaying such annotations with the associated trigger specification in a signal measurement system.
2. Related Art
Analyzers and testers are commonly available to assist in the development, manufacturing and troubleshooting of complex digital electronic/software devices and integrated circuits having incorporated therein microprocessors, random-access memories (RAM), read-only memories (ROM), and other circuits. Such analyzers and testers, generally referred to as signal measurement systems herein, include logic analyzers, digital oscilloscopes, protocol analyzers, microprocessor emulators, bit error rate testers, network analyzers, among other instruments. Logic analyzers in particular have emerged for this purpose and are commercially available from a number of vendors, such as Agilent Technologies, Inc., Tektronix, Inc., and others.
Logic analyzers are digital data acquisition instruments that allow an operator to acquire and display digital signal data from a large number of logic signals (xe2x80x9csignalsxe2x80x9d), such as those that travel over address, data and control lines of a device under test. A device under test may include one or more separately packaged devices such as those noted above, as well as other circuits and devices.
The signals are acquired from the device under test on hardwired lines referred to as channels. The channels may be physically assembled into groups commonly referred to as pods. The received signals are sampled and digitized to form signal data. Digitizing typically includes comparing a voltage magnitude of each logic signal sample to a reference voltage threshold to determine the logic state of the signal. Sampling may occur at one of a number of selectable rates, depending on the frequency at which the sampled signals change logic states. The resultant signal data are stored, under the control of a sampling clock, in a signal data memory generally having a fixed size. The data are typically stored in a sequential manner such that consecutive signal samples are stored in consecutive memory locations. Due to the quantity of signal data, signal data memory is commonly implemented as a wrap-around buffer.
Selection of the portion of the signal data that is separately stored and subsequently presented on the display is determined by an operator-defined trigger specification (also referred to as a trigger set-up). A trigger specification is functionally divided into one or more sequence levels to assist in the development and definition of complex trigger specifications. Each sequence level, in turn, includes one or more trigger branches. Each trigger branch includes one or more trigger events and an occurrence specification together identifying the condition under which functions defined by an action list of the trigger branch are performed. Typically, this includes an identification of the signal data that is to be captured.
A trigger event is defined as an occurrence of certain characteristics or properties of a signal, such as a rising or falling edge, a logic high or logic low signal state, etc. Events may also be defined based on internal resources, such internal timers, counters, etc. Typically, a branch condition specifies a number of events that occur simultaneously or in a relative time sequence. An occurrence specification identifies the number of times the trigger condition is to occur, the timing of the trigger condition relative to some other event, etc.
Thus, a trigger specification is comprised of one or more trigger sequence levels each including any number of trigger branches each of which sets forth a branch condition that causes the logic analyzer to execute the action defined in that trigger branch. Such execution results in the storage of signal data or further processing of a subsequent sequence level. A predetermined quantity of signal data occurring before and after the specified trigger condition is stored in memory for subsequent analysis.
After the trigger specification is specified, the operator can perform a measurement; that is, initiate acquisition of signal samples. When signal data capture is initiated, the signal data is compared to the trigger specification. When the trigger specification is satisfied, the signal data is captured in accordance with specified trigger control parameters or simply, trigger controls. Trigger controls identify the characteristics of the captured signal data. Subsequently, the signal data memory may be sequentially accessed and signal data displayed.
Constructing a proper trigger specification can be very a complicated and time consuming process. A common approach to developing a trigger specification is to construct and test individual portions of a trigger specification at a given time. As each sequence level or trigger branch is verified, additional layers of complexity are added to the previously verified trigger specification. For example, operators often begin trigger specification development with a simple trigger, perform an acquisition, and examine the captured data. If the results are as anticipated, then the operator adds another trigger branch or another event to an existing trigger branch further define the trigger specification. If the trigger branch or sequence level does not operate as desired, the operator will eliminate one or more of the recently-added portions of the trigger specification in an attempt to return to a trigger specification that is known to operate as desired. The operator may then perform another attempt to develop the next branch condition. This process is repeated until the current portion of the trigger specification operates as anticipated before additional layers of complexity are added.
Unfortunately, many trigger specifications are very complex with many sequence levels with complex trigger branches, all integrated into a single trigger specification to capture specific signal data. Commonly operators find it difficult to recall the function of individual trigger branches and sequence levels, particularly when the operator created many similar trigger sequence levels and specifications or has done so some distant time in the past. For example, many operators develop many complex trigger specifications that they store for use and reuse over extended periods of time. Also, trigger specifications are often shared among operators. A more experienced operator often generates and stores several generic trigger specifications for subsequent combination and modification by more novice operators to create a desired trigger specification. Unfortunately, these novice operators often cannot understand the purpose or function of the stored trigger specifications. Not only do such operators spend considerable time attempting to decipher the trigger specification, the novice operator that is not familiar with the triggering process is often prevented from invoking useful acquisitions without further assistance or guidance from a more experienced operator. This is problematic in that a more experienced operator may not be available and the labor costs associated with the measurement increase significantly. Such a burden adversely affects the efficiency with which the logic analyzer is utilized.
The present invention is a system and method for use in signal measurement systems that acquire and store signal data in accordance with a trigger specification. The present invention stores and displays operator-generated annotations with each trigger branch of a trigger specification. The annotations, referred to herein as trigger branch comments, can provide meaningful information about, for example, the trigger branch condition, occurrence specification or resulting action, as well as any other aspect of the trigger specification. The branch comments are stored with the associated trigger branch as part of the instrument configuration, and are automatically restored when the configuration data is loaded into the instrument, and printed with the associated trigger branch. The display of the trigger branch comments for each trigger branch may be controlled individually or collectively to enable the operator to configure the display of the trigger specification as needed. The trigger branch comments may be provided through the use of a text editor, programmatically or through a file or data transfer. Advantageously, the operator can annotate the trigger sequence levels and branches as they are developed to facilitate insight, understanding and recollection for the same and other operators. Providing branch comments facilitates the use of previously generated and stored trigger specifications to form a new, more complex trigger specification.
A number of aspects of the invention are summarized below, along with different embodiments of each of the summarized aspects. It should be understood that the embodiments are not necessarily inclusive or exclusive of each other and may be combined in any manner that is non-conflicting and otherwise possible, whether they be presented in association with a same or different aspect of the invention. It should also be understood that these summarized aspects of the invention are exemplary only and are considered to be non-limiting.
In one embodiment of the invention, a system for use in a signal measurement system such as a logic analyzer or oscilloscope that acquires and stores signal data in accordance with a selected trigger specification is disclosed. The selected trigger specification comprises a plurality of elements including one or more triggers sequences each having at least one trigger branch. The system is configured to display an operator-generated annotation in graphical association with an associated trigger specification element on a user interface operatively coupled to the signal measurement system. In one particular embodiment, the trigger specification elements comprise trigger branches while the trigger specification annotations comprise trigger branch comments.
In one embodiment, the system includes a text editor configured to provide a text edit area on the user interface through which operator text or editing commands are received. The system logically relates the operator-generated trigger specification annotation with the associated trigger specification element. Alternatively, the trigger specification annotations can be generated programmatically. The trigger branch comments can be displayed in an edit display mode or read-only display mode and can be graphical associated in any known manner, such as by displaying the trigger branch comment adjacent to and above the associated trigger branch.
In another embodiment, a logic analyzer is disclosed. The logic analyzer includes a graphical user interface and a trigger manager. The trigger manager is constructed and arranged to provide the operator with the ability to create, modify, view and annotate a trigger specification on the graphical user interface. The trigger manager acquires and stores signal data in accordance with a selected trigger specification. The trigger specification includes a plurality of elements including one or more trigger sequences each having at least one trigger branch. The trigger manager is configured to display the operator-generated annotation in graphical association with an associated trigger specification element on the graphical user interface. The trigger specification elements preferably comprise trigger branches while the trigger specification annotations comprise trigger branch comments. The graphical association can comprise any graphical technique such as displaying the trigger branch comment adjacent to and above the associated trigger branch.
In a further embodiment of the invention, a method for displaying operator-generated trigger branch comments on a user interface of a logic analyzer is disclosed. The method includes the steps of: displaying, for a selected trigger branch, a text edit field; receiving operator provided text in the text edit field; saving the operator provided comments with the associated trigger branch; and displaying the operator-generated trigger branch comments and the trigger specification such that each of the operator-generated trigger branch comments is graphically associated with the associated trigger branch.
Various embodiments of the present invention provide certain advantages and overcome certain drawbacks of the conventional techniques. Not all embodiments of the invention share the same advantages and those that do may not share them under all circumstances. Further features and advantages of the present invention as well as the structure and operation of various embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the drawings, like reference numerals indicate identical or functionally similar elements. Additionally, the left-most one or two digits of a reference numeral identifies the drawing in which the reference numeral first appears.